This movie takes every disaster movie cliché ever, dumps it into one big mosh pit, then waddles around in it for 2 hours and a half. Fortunately, one of those clichés is super awesome special effects, which means that despite having terrible everything, it is extremely entertaining most of the time. Unfortunately, another one of the clichés is losing steam near the ending, and this movie certainly does: by the end of it, the action is slow, unimpressive and very overdrawn. And of course, nothing makes any sense.
In a sentence:
Ridiculously entertaining for the destruction sequences, but otherwise, don't expect anything other than total rubbish.